1. Field of the Invention
This invention relates to the field of sharpening systems for ice skates, and more specifically, to the field of portable ice skate blade sharpeners.
2. Statement of the Problem
Virtually all modern ice skates, whether hockey, figure, speed, or other variety, utilize a metallic blade having a "hollow ground edge." Such an edge in contrast to a simple knife edge actually contacts the ice at two points separated by a hollow or recessed semicircular channel ground into the otherwise flat, narrow width of the blade. As with any metallic blade, the hollow ground edge becomes worn with use and loses its sharpness. This is particularly true when the ice skates are used at remote locations, such as ponds or lakes, where the edges of the ice skate blades are frequently deformed and dulled by impurities in the ice or by walking on surfaces other than ice. The edges can also be deformed through contact with other skates as commonly occurs, for example, in hockey games whether at such remote locations or in indoor rinks. Therefore, the edges must be periodically reshaped and/or sharpened to the original hollow ground profile to maintain the desired sharpness, and this frequently must be done at such remote locations or skating rinks. A need exists for a compact, portable sharpening device.
The prior art is replete with descriptions of systems for sharpening ice skate blades. For the most part, the prior art can be divided into two classes, manual devices and powered devices, and the powered devices can be subdivided into mounted and portable systems.
Manual devices typically contain an abrading stone, steel file, or other abrasive material. In use, such devices are typically held in contact with the edge and moved across the hollow ground edge with all cutting pressure and movement being manually supplied. At the elementary level, such devices would include a simple hand-held file with approximately the same radius as the inwardly curved surface of the hollow ground edge. More sophisticated manual designs include the use of guides. Regardless, such devices, while having the desirable trait of being portable, yield crude results as only the most experienced operator can maintain consistent cutting pressure. The average skater or person could not use such manual devices to sharpen blades. A clear need exists to provide a small, lightweight sharpener for use by a skater or other person that will reshape or sharpen a blade without extensive training or skill.
Powered devices, as discussed above, include both mounted and portable systems. Mounted or fixed systems might, for example, have large bench or floor-mounted components with rigid fixturing devices for holding the skate and guiding the blade in the proper orientation across a power-driven grinding member. Such large devices function very well in sharpening a blade, but are obviously not portable and usually are set up at a fixed location to which the skates have to be brought to be sharpened. These systems may weigh hundreds of pounds. Further, with such devices that include grinding wheels, it is critical to maintain proper alignment of the rotating wheel and the hollow ground edge since canting (i.e., side-to-side tilting) can dull one side of the edge while sharpening the other, and twisting of the blade about an axis perpendicular to its length can dull both sides of the edge. Some existing mounted systems have adequate fixturing to prevent canting and twisting. However, often even these devices depend on the operator to apply correct grinding pressure, hence requiring a degree of skill on the part of the operator to obtain consistent results. Furthermore, the guides found on such devices often require a degree of skill to even correctly adjust them. Finally, these sharpening systems are expensive to purchase and to maintain. A need exists even with such mounted systems for mechanisms to (1) ensure reshaping of hollow ground edges without canting and twisting, (2) maintain consistent grinding pressure, and (3) dress the grinding wheel to provide a true grinding surface.
Some devices utilizing powered rotating members have attempted to overcome the disadvantages of the mere hand-held manual tools and the expensive, heavy mounted systems while additionally offering a degree of portability. However, while many of these devices purport to be portable, they are not truly so, as they often require connection to a rotary drive such as an electric drill. Such devices, when connected to a drill, are bulky and awkward, making proper alignment with the blade difficult. Furthermore, as with many of the larger bench-mounted units, such devices often still rely on the skill of the operator to apply correct and consistent pressure to the grinding member in contact with the edge. In many cases, these supposedly portable devices lack any means to guide the rotating grinding members across the blade, and those that do often fail to effectively prevent canting and twisting of the blade. Even fewer of these devices have any means for maintaining the correct shape of the abrasive surface of the grinding element to sharpen the hollow edge of the blade. Hence, the need exists for an economical and truly portable powered sharpener. The need further exists for one that has an appropriate guide to prevent twisting and canting of the blade as it interacts with the abrasive surface and does not rely on the operator to apply consistent grinding pressure to the edge nor require any other special skills to operate in order to produce a consistent, sharpened hollow ground edge. The portable sharpener should also have a mechanism for periodically dressing the grinding surface of the grinding wheel.
3. Solution to the Problem
The present invention provides a novel solution to the aforementioned problems. With it, a blade sharpening system is provided that is inexpensive, light-weight, portable, self-powered and requires little operator skill yet yields results equal or superior to those of any of the larger and more expensive systems including those of the bench- or floor-mounted systems.
The portable blade sharpener of the present invention further provides a combined motor/grinder assembly that can be displaced within the housing of the sharpener when the blade of a skate is selectively inserted for sharpening. The weight of the motor assists in the displacement. The actual displacement of the grinding wheel against a bias mechanism provides a substantially constant grinding force directly into the hollow edge of the blade. The grinding force is independent from that supplied by the operator. The present invention ensures proper positioning of the grinding wheel to stay in the same plane as the plane of the blade. Hence, under the teachings of the present invention, the portable sharpener provides a desired grinding force directly aligned into the hollow edge of the blade as the blade is moved through the sharpener.
In another novel aspect of the present invention, a guide is provided on the upper surface of the sharpener. The guide has a formed slot, and the slot can be adjusted to different widths of blades. Hence, the user of the present invention selectively adjusts the slot to the width of the blade being sharpened. The adjustment of the slot width to the blade width is such that opposing bearing surfaces in the slot abut against the opposing side surfaces of the blade. Hence, as the blade is inserted through the slot, these bearing surfaces engage the sides of the blade. This enables the blade to easily move through the slot due to the action of the bearing surfaces, which prevent any cant or twist of the blade within the slot. Hence, as the user inserts the blade into the slot, the slot guides the blade in a true orientation over the grinding wheel, which is disposed between the bearing surfaces in the slot so that the user is assured that the hollow edge is aligned over the grinding surface of the grinding wheel over the entire length of the blade.
A novel dresser assembly is also provided in the portable sharpener of the present invention for periodically dressing the grinding surface of the grinding wheel. The dresser includes a grinding tip, a pivoting mechanism for moving the grinding tip in an arc of desired radius across the formed grinding surface of the wheel, a radius adjuster for changing the desired radius, and a location adjuster for changing the location of the grinding tip as the formed grinding surface of the wheel wears down, or if a new wheel of a different diameter is substituted. A particularly important feature of the dresser involves the radius adjuster, which allows the user of the portable sharpener of the present invention to actually adjust the radius of the hollow ground edge. For example, when the ice is very hard, a deeper hollow ground edge is required, and the dresser can be suitably adjusted.
Finally, all of the above features and mechanisms are packaged in a hand-held, lightweight, highly portable sharpener. The housing of the sharpener is designed so that each dimension is less than the length of the elongated blade being sharpened. A user of the sharpener of the present invention can quickly sharpen blades by holding the sharpener in his hand and sharpening the blade while wearing the ice skate. If a skate is damaged during use, no longer must a skater wait until he can return his skate to the location of a large, mounted sharpener; the user of the sharpener of the present invention can easily transport the sharpener to a remote location such as an ice rink or remote pool or lake to sharpen blades on location.